In recent years, a navigation system has become widely available which displays a map of an area surrounding a vehicle position, calculates a route from the vehicle position to a destination, and performs a route guide in accordance with the calculated route. In the navigation system, a guide route is displayed on a map image so as to be distinguishable from other roads (by changing a color thereof, or by making a line of the route thick, for example). Alternatively, when the vehicle reaches a location at a predetermined distance from an approaching intersection on the guide route, a guide map of the intersection is displayed on the map image (for example, as an enlarged map of the intersection). Accordingly, a driver can understand a road to be traveled or a direction to proceed at the intersection.
However, during driving, it is difficult for the driver to understand interrelation between the vehicle position displayed on the map and an actual vehicle position, and thus there has been posed a problem in that the driver makes a turn before the guide target intersection and a problem in that the driver passes through the intersection. Therefore, in order to show the driver a distance to the guide target intersection, a technique has been disclosed in which, in accordance with a distance between the vehicle position and the guide target intersection, a color of an arrow, which shows a direction to proceed at the intersection, is changed (Patent document 1).
Patent document 1: Japanese Laid-Open Patent Publication No. 6-147909